Artificial skating surface



April 28, 1970 L F, HA M ET AL 3,508,945

ARTIFICIAL SKATING SURFACE Filed Sept. 28, 1967 INVENTORS LAURENCE F.HAEMER RANDOLPH C. MC CULLE VINCENT J- STOLTZ,JF\.

ATTORNEY United States Patent US. Cl. 117-8 8 Claims ABSTRACT OF THEDISCLOSURE In both embodiments, sheets are cemented to a backing board.The vinyl sheets have cavities dispersed throughout. In the firstembodiment, the cavities are created by suspended salt crystals that canbe washed, away to leave lubricant reservoirs as the vinyl wears. In thesecond embodiment, droplets of silicone oil are suspended in the vinylto be released as lubricant as the vinyl wears.

BACKGROUND OF THE INVENTION To make ice skating the increasingly popularenter tainment spectacle it has become, expensive bulky ice makingmachinery has been required to make indoor rinks. To achieve theperfection required of ice skating in competitive sports and to providea sufficiently long season to interest amateur participants, ice skatinghadto be released from the vagaries of weather, the confinement ofclimate and the limitation of seasons. Until now, this could only beaccomplished with indoor rinks having the tremendous investment of spaceand money in artificial ice making machinery. To realize the potentialof ice skating as a popular participating sport and for night club typeentertaining, a less expensive, less bulky and more portable skatingsurface has long been needed and sought for.

All sorts of materials have been tried in an effort to make a suitableskating surface, but until the present invention none has comesufiiciently close to the properties of ice to make them usable. Anearly Patent No. 2,057,- 906 described a wax surface for skating.Linoleum was also tried, and while it provided good glide, it was toosoft and would not withstand the wear and tear of skating. A type ofmuck ice was tried using a soda mixture over wood, but this was tooslow. Even slate was tried without success. Ice skating movies have beenmade employing some type of plastic with two inches of black oil overit, but aside from the lack of durability of the plastic thedisadvantages of such an arrangement are obvious. An ice skating companyworked extensively on the use of Teflon with a lubricant, but the Teflonchipped apart and had to be nailed back together between performances.Also, Teflon provided almost no glide so that, but for the artistry ofthe skaters, the performance would have been mere walking. Such a slowsurface not only limits'the possible skating maneuvers but requiresgreat skill and is extremely tiring. A number of different substitutesfor snow have also been provided for skiers, but the require ments ofskiing are so entirely different from those of ice skating that theknowledge thus obtained is of no help. An early Patent No. 2,057,906describes the use of hard wax.

SUMMARY OF THE INVENTION The present invention is an artificial iceskating surface made of a sheet of polymeric material that has aplurality of cavities in its upper surface that serve as reservoirs forlubricant, and a film of lubricant spread over the upper surface of thesheet of polymeric material subice stantially filling such cavities.Preferably, a plurality of cavities tre dispersed throughout the sheetof polymeric material and the lubricant substantially fills such of saidcavities as open through the upper surface of the sheet of polymericmaterial.

The sheet of polymeric material mentioned above may be a laminate.Commonly, the sheet of polymeric material Will be cemented or otherwisemounted on a rigid backing material, such as a fiberboard, plywood orother suitable materials for support. This combination provides arugged, lightweight, inexpensive substitute for ice that can veryclosely approximate the skating characteristics of ice.

The cavities in the upper surface provides a roughened surface whichwill readily hold the edge of a skate. In the preferred form in whichthe cavities are dispersed throughout the sheet, the surface textureremains uniform as the material wears from use because of successivelylower cavities being opened to the upper surface as higher ones are wornaway. It has been found essential that the lubricant wet the surface ifadequate glide is to be provided, and glide is essential to skating. Thecavities serve not only to roughen the surface, but also to hold thelubricant to insure that there will always be adequate lubricantuniformly spread over the surface. While properly conditioned ice at theoptimum temperature still remains unequaled as a skating surface, thepresent invention provides the first artificial skating surface thatapproximates ice closely enough to be capable of popular, as well asprofessional, use. Moreover, it is inexpensive, easy to install andlight enough to be portable.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a side elevation in section of a segment of an artificial iceskating surface embodying the present invention showing the surfacematerial, a portion of an ice skate blade engaging the surface and thebacking for the surface.

FIG. 2 is a similar side elevation in section of a second embodiment ofthe present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The segment of the embodimentin FIG. 1 illustrates a sheet 1 of polymeric material cemented to abacking board 2 supported by a suitable adhesive 3. A thin film oflubricant 4 is shown spread over the upper surface 5 of the sheet 1 ofpolymeric material. A portion of a skate blade 6 is shown in sectionstanding on the upper surface 5 of the sheet 1 of polymeric material.The skate blade 6 has the usual concave bottom surface 7 to define twoedges 8- and 9 by which the skating surface is engaged for propulsionand maneuvering. Dispersed throughout the sheet 1 of polymeric materialare a plurality of small cavities 10 which combine to totalapproximately 25 percent of the volume of the sheet 1 of polymericmaterial. The cavities 10 are created by a suspension of sodium chloridecrystals 11 which define the shape of and fill the cavities.

The first embodiment is made by calendering and extruding a vinylcompound. The salt crystals 11 are mixed 7 with the vinyl compound toprovide the cavities 10. The

compound is an admixture, in parts by weight that is the same as vinylfloor covering, to wit: polyvinyl chloride resin 100, dioctyl phthalateplasticizer 17.4, butyl cyclohexyl phthalate 7.5, epoxidized soya oil6.0 barium cadmium stabilizer 5.5, and stearic acid 0.3. Color pigmentsmay be added if desired. The sodium chloride crystals 11 provide 35.5parts by weight of the total mixture and have the following screenanalysis: None is larger than 40 mesh; 5.6 percent is coarser than 80mesh; 35.6 percent is coarser than 100 mesh; 92 percent is coarser than325 mesh; but only 8 percent is finer than 325 mesh. Actually materialuniformly finer than 300325 mesh would be too fine to provide adequateretention of lubricant, but the crystals may be as large as permitted bythe minimal thickness of the polymer sheet 1. Sodium chloride salt hasbeen chosen because it is readily available in various screened crystalsizes and it is soluble in water. However, any solid granular substancesoluble in a solvent that does not attack the polymer sheet 1 itself mayhe used. The purpose of the solid granular substance, in this case thesalt crystals 11, is in the first instance to define the cavities 10and, secondly, to be readily Washed away to provide reservoirs forlubricant.

The lubricant employed is a commercially available silicone oil having aviscosity of approximately 100 centistokes. Other lubricants, however,may also be used. It has been found that the lubricant must Wet thesurface 5 upon which the skate blade 6 is to glide. Also, the lubricantmust have the viscosity and film strength to support the pressures ofthe skate blade 6. Thus, with some materials water might wet thesurface, but it would lack film strength, and with other materials andlubricants there may be adequate film strength but no wetting of thesurface. (Efforts to employ Teflon as a skating surface are believed tohave failed largely because of the lack of a lubricant capable ofwetting the surface of the Teflon.) In the second embodiment, a polymersheet 12 is anchored to a supporting board 13 by a suitable adhesive 14,and again the skate blade 6 is shown riding on an upper surface 15 ofthe sheet 12 of polymeric material. Dispersed through the polymer sheet12 are cavities 16 filled with silicone oil droplets 17. The secondembodiment is formulated using a plastisol and the silicone oil 17 is alubricant which is dispersed through the material before it is hardened.The polymer sheet 12 of the second embodiment is then made up of thefollowing admixture of components, the parts by weight being indicated:Polyvinyl chloride plastisol resin 55 .0; polyvinyl chloride largeparticle size resin 45.0; dioctyl phthalate 17.5; butyl cyclohexylphthalate 7.5; epoxidized soya oil 6.0; liquid barium cadmium stabilizer3.0 and viscosity reducer (polyethylene glycol 200 monolaurate) 1.0. Thesilicone oil 17 of 100 centistoke viscosity 10.0 parts by weight anddisperses readily in the plasticizer, but it can also be dispersed inthe completed plastisol before fusion. It is critical that thelubricant, in this case silicone oil 17, be immiscible in the materialof the polymer sheet so that it will form discrete droplets dispersedthrough the polymer sheets, instead of attacking the polymer sheet 12itself. Also, it is particularly important in this embodiment that ofthe total volume of the polymer sheet 12, the cavities 16 containing thesilicone oil droplets 17 comprise no more than 50 percent, and about 25percent seems to be optimum. If the cavities 16 containing silicondroplets 17 make up an excessive portion of the volume of the polymersheet 12, a spongy mass will result that will be too soft to serveadequately for the skating surface and will exude too much lubricantunder pressure.

In both embodiments, as polymer sheet 1 and 12 is used it will wear awayeliminating some of the higher cavities 16, in the upper surface 5 and15 and uncovering other cavities 10 and 16 that had originally beenbelow the upper surface 5 and 15. As a result, the same surface textureis retained throughout the life of the polymer sheet 1 and 12 and, inthe second embodiment, a constant supply of lubricant from the siliconeoil droplets .17 is automatically provided. Even with extensive use,however, it should be pointed out that the life of the polymer sheet 1and 12 of the first and second embodiments, respectively, is measured inyears. If dust, polymer shavings and other debris collects on thesurface 5 and 15, it may be necessary from time to time to wash thesurface with detergent, in which case additional lubricants might haveto be added after the washing.

irregularity in the upper surface 5 and 15, respectively, of the polymersheet 1 and 12, respectively, serve two functions: first, they providereservoirs for lubricants; and second, they allow the skate blade 6,edges 8 and 9 to grasp the surface for propulsion and maneuvering. Forthe latter function, the size and number of the irregularities requiredwill depend upon the hardness of the material used in the polymer sheet1 and 12. In this connection it is wirth noting that the polymer sheet 1and 12 need not be a homogeneous material throughout, but might be alaminate of two or more separate materials having different hardnesscharacteristics. However, it has been found that a hardness rangebetween Shore D30 and Shore D70 is suitable. As the material becomessofter, smaller and fewer irregularities are needed to allow gripping bythe edges 8 and 9 of the skate blade 6, but as the material becomesharder, more and larger irregularities are required. In the firstembodiment, then, the size of the salt cystals 11 may be determined inpart by the hardness of the material used by the polymer sheet 1. Inaddition to the materials shown in the specific examples, the followingpolymers will also be suitable for use as the polymeric sheet 1 and 12:polyvinyl chloride copolymers and blends, chlorinated polyethylene,polypropylene, polyethylene, ionomer resin, copolymers of polypropyleneand polyethylene, copolymers of ethylene and vinyl acetate, copolymersof ethylene and acrylates, polystyrene, acrylonitrile-styrene-butadieneterpolymers, blends of polystyrene with S-BR or NBR, polymethylmethacrylate, urethane polymers, cellulose acetate butyrate, ethylcellulose, polyvinyl alcohol, epoxy resin compounds. These materialscombine hardness, toughness, and surface characteristics which, alongwith a suitable lubricant, will have skating characteristics closelyenough approximating ice to be successfully usable as a skating surface.

It. is important to note that although cavities 10 and 16 are dispersedthroughout the polymer sheet 1 and 12, respectively, a sponge of foammaterial is not employed. The. sponge and foam materials are too softand found to be unsuitable for use in an artificial skating surface. Forthat reason, it is important that aggregate volume of the cavities 10and 16 be limited to less than half of the total volume .of the polymersheet 1 and 12, respectively.

The invention has thus far been described in relation to the preferredform in which cavities are dispersed throughout the polymeric sheet.However, a sheet of polymeric material can also be used in which thecavities, or irregularities, are formed only in the upper surfacethereof. The cavities will function as reservoirs for the lubricant and-'also provide the roughened surface necessary to hold the edge of theskate. The depth of the cavities or irregularities will be dependentupon the hardness of the material. The sheet of polymeric materialhaving the hardness and durability described in relation to thepreferred embodiments can be formed with cavities on its upper surfaceby sanding, buffing, molding, embossing or machining. As previouslydescribed, a lubricant is used which wets the surface and is containedin the surface cavities. Such a surface effect will eventually be wornsmooth and it will then be necessary to refinish the same in contrast tothe preferred embodiments in which a new upper surface with cavities iscontinuously being exposed.

As can be seen from the foregoing description, the materials used incarrying out the present invention are determined by physical propertiesand not chemical composition, except, insofar as the physical propertiesare determined by chemical composition. However, the essential featuresare physical and accordingly no attempt is made to define the inventionchemically. Inasmuch as numerous materials presently known as well asnumerous materials to be developed in the future share the necessaryproperties for use in the present invention, the invention may appear inmany forms and embodiments. Accordingly, the

invention is not limited to the two preferred embodiments describedabove but rather in the claims that follow.

What is claimed is:

1. An artificial ice skating surface comprising:

a fiat sheet of polymeric material of a hardness within the range ofShore D30 and Shore D70 and having an upper skating surface;

a plurality of cavities dispersed throughout said polymeric material toserve as reservoirs for lubricant, some of said cavities opening throughsaid upper surface, said cavities comprising not more than 50% by volumeof said sheet and being defined by and containing a crystalline solublesalt adapted to be washed away as said cavities are exposed through saidupper skating surface, the major portion of said salt being coarser than325 mesh;

and a lubricant capable of wetting said upper surface of said sheet ofpolymeric material, said lubricant spread over said upper surface in athin film and substantially filling said cavities opening through saidupper surface.

2. An artificial ice skating surface in accordance with claim 1 whereina substantial portion of said salt is in the size range between 80 meshand 325 mesh.

3. An artificial ice skating surface in accordance with claim 2 whereinsaid polymeric material is an admixture in parts by weight of about 100parts polyvinyl chloride resin, 17.5 parts of dioctyl phthalateplasticizer, 7.5 parts of butyl cyclohexyl phthalate, 6.0 parts ofepoxidized soya oil, 5.5 parts of barium cadmium stabilizer, and 0.3parts of stearic acid.

said salt comprises approximately 25% of the volume of said sheet ofpolymeric material and is dispersed throughout said admixture, said salthaving the following approximate screen analysis: none larger than 40mesh, 5.6 percent coarser than 80 mesh, 35.6 percent coarser than 100mesh, and 92 percent coarser than 325 mesh, and

said lubricant is a silicone fluid.

4. A method of making an artificial ice skating surface comprising:

forming a polymeric material having a hardness in the range of Shore D30and Shore D70 into a fiat sheet with an upper skating surface and with aplurality of discrete cavities dispersed throughout said sheet to serveas reservoirs for lubricant and including cavities opening through saidupper surface, said cavities comprising not more than 50% by volume ofsaid sheet,

and applying a lubricant over said upper surface which will wet saidupper surface and form a thin film and substantially fill said cavitiesopening through said upper surface.

5. The method of making an artificial ice skating surface in accordancewith claim 4 wherein said cavities constitute approximately 25% of thevolume of said sheet of polymeric material.

6. A method of making an artificial ice skating surface comprising:

forming a polymeric material having a hardness in the range of Shore D30and Shore D into a flat sheet with an upper skating surface and with aplurality of discrete cavities dispersed throughout said sheet includingcavities opening through said upper surface. said cavities comprisingnot more than 50% by volume of said sheet and said cavities containingand being defined by a lubricant that is immiscible with said polymericmaterial and which lubricant wets said upper surface to form a thin filmon said upper surface and to substantially fill said cavities openingthrough said upper surface.

7. The method of making an artificial ice skating surface in accordancewith claim 6 wherein said lubricant is a silicone fluid.

8. A method of making an artifical ice skating surface comprising:

forming a polymeric material having a hardness in the range of Shore D30and Shore D70 into a flat sheet having an upper skating surface,

forming a plurality of cavities in said upper surface to act asreservoirs for a lubricant, said cavities each having a maximumdimension substantially less than the width of the blade of an iceskate,

and applying a lubricant over said upper surface which will wet saidupper surface to form a thin film over said surface and substantiallyfilling said cavities.

References Cited UNITED STATES PATENTS 2,3 32,514 10/ 1943 Holtzclaw.

2,335,958 12/1943 Parker 25211 XR 2,500,573 3/1950 Rockoff.

2,567,804 9/1951 Davies.

3,055,297 9/1962 Leeds.

3,171,699 3/1965 Maxey 2S212 XR 3,407,713 10/1968 Heckman.

3,431,203 4/ 1969 Hartmann et al. 25212.2

DAVID KLEIN, Primary Examiner U .8. Cl. X.R.

@2 3 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,508, 945 Dated April ZB 15L) Inventor(s) LAURENCE F. HAEMER RANDOLPH C.McCULLEY VINCENT J. STOLTZ, JR.

It is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below:

C olumn 2, Line 2 for "cavities tre dispersed" read --cavities aredispersed-- Column 2, Line 68 for plasticizer 17. 4, read --plasticizer17. 5,

Column 2, Line 69 for 611 6. o barium" read "011 6.0, barium-- Column 4,Line 10 for "wirth" read -worth- Column 4, Line 40 for "sponge of foam"read -sponge or foam-- Milt-:3

QSEAL) Aneat:

Edward M. Fletcher, Jr. mm B. 505m JR Attesting Officer MB! 01 Patents

